A drilling riser pipe, commonly referred to as riser, consists of a series of tubular elements referred to as joints, assembled by mechanical connectors. The tubular elements generally consist of a main tube at the ends of which connecting parts are welded. The main tube is fitted with auxiliary lines commonly referred to as kill line, choke line, booster line and hydraulic line, which allow fluid circulation between the bottom and the surface. The auxiliary lines are usually arranged around the main tube, hence their designation as peripheral lines. The tubular elements are assembled on the drilling site, from a floating support. The riser goes down through the water depth as the tubular elements are assembled to one another, until it reaches the wellhead located on the sea bottom. Floating elements are arranged along the riser so as to lighten the weight thereof in the water.
The development of offshore reservoirs at very great water depths and/or of high-pressure reservoirs requires using risers whose weight and cost are penalizing.
The present invention aims to modify the connection part, commonly referred to as replaceable stab, of the tubes forming the auxiliary lines so as to reduce the sealing section of the connection part, in order to reduce the stresses applied to the entire riser, and thus to reduce the dimensions of the various elements making up the riser, notably to reduce the thickness of the tubes and the diameter of the floats.